@Override
public ITree filterProduction(ITree tree, Object environment) {
String cons = TreeAdapter.getConstructorName(tree);
if (cons != null) {
Environment env = (Environment) environment;
Result<IValue> var = env.getFrameVariable(cons);
if (var != null && var instanceof ICallableValue) {
ICallableValue function = (ICallableValue) var;
try {
Result<IValue> result = null;
if (TreeAdapter.isContextFree(tree)) {
// For context free trees, try it without layout and literal arguments first.
result = call(function, TreeAdapter.getASTArgs(tree));
}
if (result == null) {
result = call(function, TreeAdapter.getArgs(tree));
}
if (result == null) {
return tree;
}
if (result.getType().isBottom()) {
return tree;
}
if (!(result.getType() instanceof NonTerminalType
&& SymbolAdapter.isEqual(
((NonTerminalType) result.getType()).getSymbol(), TreeAdapter.getType(tree)))) {
// do not call the function if it does not return the right type
return tree;
}
return (ITree) result.getValue();
} catch (Filtered f) {
return null;
}
}
}
return tree;
}
@Override
protected Result<IBool> equalToConcreteSyntax(ConcreteSyntaxResult that) {
IConstructor left = this.getValue();
IConstructor right = that.getValue();
if (TreeAdapter.isLayout(left) && TreeAdapter.isLayout(right)) {
return bool(true, ctx);
}
if (TreeAdapter.isAppl(left) && TreeAdapter.isAppl(right)) {
IConstructor p1 = TreeAdapter.getProduction(left);
IConstructor p2 = TreeAdapter.getProduction(right);
if (!p1.isEqual(p2)) {
return bool(false, ctx);
}
IList l1 = TreeAdapter.getArgs(left);
IList l2 = TreeAdapter.getArgs(right);
if (l1.length() != l2.length()) {
return bool(false, ctx);
}
for (int i = 0; i < l1.length(); i++) {
IValue kid1 = l1.get(i);
IValue kid2 = l2.get(i);
// Recurse here on kids to reuse layout handling etc.
Result<IBool> result =
makeResult(kid1.getType(), kid1, ctx).equals(makeResult(kid2.getType(), kid2, ctx));
if (!result.getValue().getValue()) {
return bool(false, ctx);
}
if (TreeAdapter.isContextFree(left)) {
i++; // skip layout
}
}
return bool(true, ctx);
}
if (TreeAdapter.isChar(left) && TreeAdapter.isChar(right)) {
return bool((TreeAdapter.getCharacter(left) == TreeAdapter.getCharacter(right)), ctx);
}
if (TreeAdapter.isAmb(left) && TreeAdapter.isAmb(right)) {
ISet alts1 = TreeAdapter.getAlternatives(left);
ISet alts2 = TreeAdapter.getAlternatives(right);
if (alts1.size() != alts2.size()) {
return bool(false, ctx);
}
// TODO: this is very inefficient
again:
for (IValue alt1 : alts1) {
for (IValue alt2 : alts2) {
Result<IBool> result =
makeResult(alt1.getType(), alt1, ctx).equals(makeResult(alt2.getType(), alt2, ctx));
if (result.getValue().getValue()) {
// As soon an alt1 is equal to an alt2
// continue the outer loop.
continue again;
}
}
// If an alt1 is not equal to any of the the alt2's return false;
return bool(false, ctx);
}
return bool(true, ctx);
}
return bool(false, ctx);
}